O-Acetyl homoserine acts as a precursor of methionine, which is one of the essential amino acids in the body. Methionine has been widely used a component of medical infusion solutions and raw materials for medicinal products as well as an animal feed and food additive.
Methionine can be biologically or chemically synthesized. Recently, a two-step process, in which an L-methionine precursor produced by fermentation is converted to L-methionine by an enzyme reaction, was disclosed (International Publication No. WO 2008/013432). In the above two-step process, O-succinyl homoserine and O-acetyl homoserine may be used as the methionine precursor, and it is important that O-acetyl homoserine be produced in high yield for large-scale cost-effective production of methionine.